Automatic electric cut-out



April 14, 1936. R. KURZ AUTOMATIC' ELECTRIC CUTf-OUT Filed June 2, 1952 `Patented pr. 14, 1936 PATENT ori-ICE I .AU'roMA'rxc ELECTRIC cU'r-oU'r -Richard Kurz, Stuttgart, Germany,- assigner to Robert Bosch Aktiengesellschaft, Stuttgart,

Germany Application June 2, 1932. Serial No. 815,006 In Germany June 13, 1931 1 claim. -(ci. zoo-sii ,This invention relates to automatic electric cutouts particularly for the electric systems of automobiles. A

In electrical installations on vehicles an Vauto- 5 matic cut-out switch is usually provided which connects the dynamo to the-battery on the production of a certaimvoltage. In order that the sparks occurring on the opening and closing of the switch may not destroy the switch contacts.

it is known to employ a pair oi preliminary contacts which are in parallel with thepair ot main contacts.

The object of the present invention is to provide means whereby the preliminary contacts are suddenly disengaged at a predetermined position o! the armatureI of the switch or its return to the position of rest.

According tothe invention the foregoing means may comprise a stopplate on the armature oi the switch which engages the spring carrying the preliminary contact at a predetermined position on the return of the armature to the position of rest.

An example of construction oi the invention is shown partly in section in the accompanying drawing. 4

The automatic switch consists of an electromagnet a and an armature b having an arm bent at right angles to' which a contact spring` c, to- 80 gether with a stop-plate d, is riveted. The iastening rivet e serves at the same time asy switch contact and co-operates with a stationary counter-contact l. A contact 'n provided on the contact spring c co-operatec with a counter-contact $5 h.. The pair of main contacts is denoted by e. f

andthe pair of preliminary contacts by a, h.

When the armature b is attracted by theelectromagnet, the contact y nrst comes against its counter-contact h, so that the current hows 40 through the-closed pair of preliminary contacts a.' h. When the armature is further attracted, the pair oi' main contacts e. f, is then closed.

On the return of the armature a, the pair of main contacts e. f is nrst opened, the current still iiowing through the closed pair of preliminary contacts a. h. On the further backward movement o! the armatures, the stop-plate d suddenly Y lifts the contact spring c from the contact h, whereby sparking and the burning of the contacts is diminished. 'Ihe contact spring c cannot be considerably heated by the sparking arising from a light contacting oi' the contacts in s comparison with previous forms oi construction. in which the contact spring might be so strongly heated by the contact sparking that it losas its predetermined tension.

As can be seen from the drawing, the stop-plate 10 dcan be fastened in'a simple mannertogether with the contact spring c to the armature a.

I declare. that what I claim is:

In an electric switch oi the electromagnetic type; the combination with an electromagnet and ll a pivoted armature having a portion in adjacent opposition to a pole of said electromagnet for actuation oi' said armature by said electromagnet and .another portion disposed to one side or laterally oi said electromagnet out of alignment 20 with the polar axis thereof, of a pair of stationary contacts entirely to saidsone side of said electromagnet and with both contacts of said pair on the same side of said laterally-disposed portion o! said amature., a main contact carried by said 25 laterally-disposed portion of said armature and cooperating with one of said stationary contacts, a leaf spring carried by said laterally-disposed portion ot said amature, a preliminary contact secured to said leaf spring at a point thereon lat- 30 erally spaced' from said electromagnet and cooperating with the other oi said stationary contacts,

said armwre being movable .by said electromagnetjrom a position of rest to bring said prelimmary-and main contacts into engagement with 3 5 said .stationary contacts and said armature automatically returning to said position of rest upon de-energization of said electromagnet. and :t rigid plate secured to said laterally-disposed portion of said armature and engaging said spring toA-o abruptly disengage said preliminary contact from its cooperating stationary contact on said return movement of said armature, said main contact being so formed as also to constitute means securingsaid lea! spring and plate to said amature. 45

RICHARD KURZ. 

